Management of glenoid bone loss with impaction and structural bone grafting in reverse shoulder arthroplasty.

INTRODUCTION: Glenoid bone loss is a commonly encountered problem in complex primary and revision shoulder arthroplasty. Addressing glenoid bone loss is critical to avoid complications like early loosening, impingement, notching and instability. A large number of techniques like bone grafting using autograft or allograft, eccentric reaming, augmented base plates, patient-specific instrumentations and custom-made implants are available to tackle bone loss. MATERIALS AND METHODS: We prospectively collected the data of all patients with glenoid defects undergoing primary or revision reverse shoulder replacement between 2004 and 2017. This included demographic data, ranges of motion, Constant-Murley score and Subjective Shoulder Value (SSV). A pre-operative CT scan was done as well to plan the surgery and calculate the glenoid version. At each follow-up, the clinical function and shoulder scores were assessed. Additionally, the radiographs were assessed for graft incorporation, evidence of lysis and calculation of glenoid version. RESULTS: Between 2004 and 2017, 37 patients underwent glenoid bone grafting during reverse shoulder arthroplasty. Average age was 72 years (range 46-88). Indications for surgery were cuff tear arthropathy (6 patients); revision of failed other prosthesis (23); primary osteoarthritis (4); rheumatoid arthritis (3); and second-stage revision for infection (1). The glenoid defect was contained in 24 patients, and therefore, impaction graft with a combination of bone graft substitute and/or humeral head autograft was performed. In 13 patients the glenoid defect was severe and uncontainable and therefore a graft-implant composite glenoid was implanted using humeral head autograft or allograft. Average follow-up was 3.6 years (range 1-10). Mean Constant score improved from 34 before surgery to 63 after surgery. Mean SSV score improved from 0.9/10 to 8.3/10. Active movements improved significantly with forward elevation increasing from 54° to 123°; abduction from 48° to 123°; external rotation from 24° to 38°; internal rotation from 57° to 70°. Radiographs at final follow-up showed no radiolucencies around the glenoid component and no evidence of loosening of the implant. In 2 cases there was a grade I notching. There was 100% survivorship at the last follow-up. CONCLUSION: Impaction bone grafting along with structural grafting when required is an effective and reproducible way of managing severe glenoid bone loss. This technique gives consistent and good clinical and radiological results.

Hand posture, but not vision of the hand, affects tactile spatial resolution in the grating orientation discrimination task.

The grating orientation discrimination task (GOT) is a sensitive and reliable measure of tactile spatial resolution, or acuity. We used the GOT in three experiments to investigate the effects of hand posture and hand visibility on spatial acuity. Participant sex and experimental design were also manipulated. Healthy adult participants received brief touches to their index fingertips of grated, domed objects. Their task was to decide whether the gratings ran 'along' or 'across' their finger. Measures of the smallest grating width for which participants could reliably discriminate between orientations were recorded as threshold. Experiment 1 evaluated the effect of two- versus one-interval discrimination, hand used and participant sex. Experiments 2 and 3 evaluated the effects of hand visibility (visible or covered) and hand posture (in front or to the side). Females were better than males; the two-interval task resulted in lower thresholds than the one-interval task; and left and right hand thresholds were not significantly different. Most importantly, while hand visibility did not have a significant effect on the task, thresholds were affected by hand posture-worse when the hand was oriented to the side of the body than in front. These results replicate previously reported effects of sex (or finger size), but failed to replicate the so-called 'visual enhancement of touch' (VET) effect. We also report a meta-analysis of 27 VET studies, finding a significant effect of 'non-informative' vision on tactile perception. Our novel finding is that hand posture affects tactile acuity.

What influences students' abilities to critically evaluate scientific investigations?

Critical thinking is the process by which people make decisions about what to trust and what to do. Many undergraduate courses, such as those in biology and physics, include critical thinking as an important learning goal. Assessing critical thinking, however, is non-trivial, with mixed recommendations for how to assess critical thinking as part of instruction. Here we evaluate the efficacy of assessment questions to probe students' critical thinking skills in the context of biology and physics. We use two research-based standardized critical thinking instruments known as the Biology Lab Inventory of Critical Thinking in Ecology (Eco-BLIC) and Physics Lab Inventory of Critical Thinking (PLIC). These instruments provide experimental scenarios and pose questions asking students to evaluate what to trust and what to do regarding the quality of experimental designs and data. Using more than 3000 student responses from over 20 institutions, we sought to understand what features of the assessment questions elicit student critical thinking. Specifically, we investigated (a) how students critically evaluate aspects of research studies in biology and physics when they are individually evaluating one study at a time versus comparing and contrasting two and (b) whether individual evaluation questions are needed to encourage students to engage in critical thinking when comparing and contrasting. We found that students are more critical when making comparisons between two studies than when evaluating each study individually. Also, compare-and-contrast questions are sufficient for eliciting critical thinking, with students providing similar answers regardless of if the individual evaluation questions are included. This research offers new insight on the types of assessment questions that elicit critical thinking at the introductory undergraduate level; specifically, we recommend instructors incorporate more compare-and-contrast questions related to experimental design in their courses and assessments.

Differential and defective transcription of koala retrovirus indicates the complexity of host and virus evolution.

Koala retrovirus (KoRV) is unique amongst endogenous (inherited) retroviruses in that its incorporation to the host genome is still active, providing an opportunity to study what drives this fundamental process in vertebrate genome evolution. Animals in the southern part of the natural range of koalas were previously thought to be either virus-free or to have only exogenous variants of KoRV with low rates of KoRV-induced disease. In contrast, animals in the northern part of their range universally have both endogenous and exogenous KoRV with very high rates of KoRV-induced disease such as lymphoma. In this study we use a combination of sequencing technologies, Illumina RNA sequencing of 'southern' (south Australian) and 'northern' (SE QLD) koalas and CRISPR enrichment and nanopore sequencing of DNA of 'southern' (South Australian and Victorian animals) to retrieve full-length loci and intregration sites of KoRV variants. We demonstrate that koalas that tested negative to the KoRV pol gene qPCR, used to detect replication-competent KoRV, are not in fact KoRV-free but harbour defective, presumably endogenous, 'RecKoRV' variants that are not fixed between animals. This indicates that these populations have historically been exposed to KoRV and raises questions as to whether these variants have arisen by chance or whether they provide a protective effect from the infectious forms of KoRV. This latter explanation would offer the intriguing prospect of being able to monitor and selectively breed for disease resistance to protect the wild koala population from KoRV-induced disease.

Bespoke magnetic field design for a magnetically shielded cold atom interferometer.

Quantum sensors based on cold atoms are being developed which produce measurements of unprecedented accuracy. Due to shifts in atomic energy levels, quantum sensors often have stringent requirements on their internal magnetic field environment. Typically, background magnetic fields are attenuated using high permeability magnetic shielding, with the cancelling of residual and introduction of quantisation fields implemented with coils inside the shield. The high permeability shield, however, distorts all magnetic fields, including those generated inside the sensor. Here, we demonstrate a solution by designing multiple coils overlaid on a 3D-printed former to generate three uniform and three constant linear gradient magnetic fields inside the capped cylindrical magnetic shield of a cold atom interferometer. The fields are characterised in-situ and match their desired forms to high accuracy. For example, the uniform transverse field, Bx, deviates by less than 0.2% over more than 40% of the length of the shield. We also map the field directly using the cold atoms and investigate the potential of the coil system to reduce bias from the quadratic Zeeman effect. This coil design technology enables targeted field compensation over large spatial volumes and has the potential to reduce systematic shifts and noise in numerous cold atom systems.

Plasmonic enhancement of aqueous processed organic photovoltaics.

Sodium tungsten bronze (Na x WO3) is a promising alternative plasmonic material to nanoparticulate gold due to its strong plasmonic resonances in both the visible and near-infrared (NIR) regions. Additional benefits include its simple production either as a bulk or a nanoparticle material at a relatively low cost. In this work, plasmonic Na x WO3 nanoparticles were introduced and mixed into the nanoparticulate zinc oxide electron transport layer of a water processed poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) nanoparticle (NP) based organic photovoltaic device (NP-OPV). The power conversion efficiency of NP-OPV devices with Na x WO3 NPs added was found to improve by around 35% compared to the control devices, attributed to improved light absorption, resulting in an enhanced short circuit current and fill factor.

Ready student one: Exploring the predictors of student learning in virtual reality.

Immersive virtual reality (VR) has enormous potential for education, but classroom resources are limited. Thus, it is important to identify whether and when VR provides sufficient advantages over other modes of learning to justify its deployment. In a between-subjects experiment, we compared three methods of teaching Moon phases (a hands-on activity, VR, and a desktop simulation) and measured student improvement on existing learning and attitudinal measures. While a substantial majority of students preferred the VR experience, we found no significant differences in learning between conditions. However, we found differences between conditions based on gender, which was highly correlated with experience with video games. These differences may indicate certain groups have an advantage in the VR setting.

Oxytocin increases inhibitory synaptic transmission and blocks development of long-term potentiation in the lateral amygdala.

Oxytocin (OT) is a neuroactive peptide that influences the processing of fearful stimuli in the amygdala. In the central nucleus of the amygdala, the activation of OT receptors alters neural activity and ultimately suppresses the behavioral response to a fear conditioned stimulus. Receptors for OT are also found in the lateral amygdala (LA), and infusion of OT into the basolateral amygdala complex affects the formation and consolidation of fear memories. Yet, how OT receptor activation alters neurons and neural networks in the LA is unknown. In this study we used whole cell electrophysiological recordings to determine how OT-receptor activation changes synaptic transmission and synaptic plasticity in the LA of Sprague-Dawley rats. Our results demonstrate that OT-receptor activation results in a 200% increase in spontaneous inhibitory transmission in the LA that leads to the activation of presynaptic GABAB receptors. The activation of these receptors inhibits excitatory transmission in the LA, blocking long-term potentiation of cortical inputs onto LA neurons. Hence, this study provides the first demonstration that OT influences synaptic transmission and plasticity in the LA, revealing a mechanism that could explain how OT regulates the formation and consolidation of conditioned fear memories in the amygdala.NEW & NOTEWORTHY This study investigates modulation of synaptic transmission by oxytocin (OT) in the lateral amygdala (LA). We demonstrate that OT induces transient increases in spontaneous GABAergic transmission by activating interneurons in the basolateral amygdala. The resultant increase in GABA release in the LA activates presynaptic GABAB receptors on both inhibitory and excitatory inputs onto LA neurons, reducing release probability at these synapses. We subsequently demonstrate that OT modulates synaptic plasticity at cortical inputs to the LA.

The effect of standard laboratory diets on estrogen signaling and spatial memory in male and female rats.

Phytoestrogens are plant-derived compounds that can modulate estrogen activity in the brain and periphery. Laboratory rodent diets are typically high in soy-based phytoestrogens and therefore may influence neurophysiological and behavioural measures that are sensitive to estrogen signaling. Here we assessed such measures in rats (males and females) fed Australian made diets that varied in their soy levels. We found that a low-soy diet promoted greater weight, and lower levels of plasma estradiol, particularly in male rats. It also produced sex-specific effects on estrogen receptor gene expression in the brain, increasing ESR2 expression in the hippocampus and prefrontal cortex in female rats, and decreasing dopamine D1 receptor gene expression in the striatum of both male and female rats. We also found a dietary effect on short-term place recognition memory, but this was independent of soy levels in the diet. These results demonstrate that the choice of rodent laboratory diet can influence physiology, neurobiology and behavior, particularly on measures related to estrogen signaling.

Tools for Change: Measuring Student Conceptual Understanding Across Undergraduate Biology Programs Using Bio-MAPS Assessments.

Assessing learning across a biology major can help departments monitor achievement of broader program-level goals and identify opportunities for curricular improvement. However, biology departments have lacked suitable tools to measure learning at the program scale. To address this need, we developed four freely available assessments-called Biology-Measuring Achievement and Progression in Science or Bio-MAPS-for general biology, molecular biology, ecology/evolution, and physiology programs. When administered at multiple time points in a curriculum, these instruments can provide departments with information on how student conceptual understanding changes across a major and help guide curricular modifications to enhance learning.

Temporal and interspecific variation in feather mercury in four penguin species from Macquarie Island, Australia.

We measured mercury (Hg) concentrations in feathers from four penguin species collected on Macquarie Island, Southern Ocean, to 1) establish baseline Hg concentrations; and 2) compare Hg from samples collected in 2002 ("modern") and from museum specimens collected between 1937 and 1976 ("historic"). Inter-specific differences in feather Hg reflected known differences in habitats and diversity of diets: benthic-foraging Gentoo penguins and Rockhopper penguins that foraged both inshore and offshore had significantly higher feather mercury than the more pelagic, specialist foraging King and Royal penguins. Hg significantly decreased between historic and modern samples in King and Royal penguins. This decrease could be due to changes in either diet, foodwebs, or atmospheric Hg input and sources in the Southern Hemisphere. Because Macquarie Island is home to 2.8 million marine animals, these data may indicate that other species that forage and breed in this region are also exposed to low Hg concentrations in this environment.

Exploring bias in mechanical engineering students' perceptions of classmates.

Gender disparity in science, technology, engineering, and math (STEM) fields is an on-going challenge. Gender bias is one of the possible mechanisms leading to such disparities and has been extensively studied. Previous work showed that there was a gender bias in how students perceived the competence of their peers in undergraduate biology courses. We examined whether there was a similar gender bias in a mechanical engineering course. We conducted the study in two offerings of the course, which used different instructional practices. We found no gender bias in peer perceptions of competence in either of the offerings. However, we did see that the offerings' different instructional practices affected aspects of classroom climate, including: the number of peers who were perceived to be particularly knowledgeable, the richness of the associated network of connections between students, students' familiarity with each other, and their perceptions about the course environment. These results suggest that negative bias against female students in peer perception is not universal, either across institutions or across STEM fields, and that instructional methods may have an impact on classroom climate.

Long-term impacts of antibiotic allergy testing on patient perceptions and antibiotic utilization.

OBJECTIVES: To define the long-term impacts of antibiotic allergy testing (AAT) on patient allergy perception and antibiotic utilization. METHODS: Patients were identified from a prospective AAT database as having completed testing during a 15 month period beginning January 2017. Patients were contacted for a follow-up survey at least 12 months post-AAT. For those contacted, baseline demographics, antibiotic allergy label (AAL) history, age-adjusted Charlson comorbidity index, infection history, antibiotic de-labelling (≥1 AAL removed following AAT) and antibiotic usage for 12 months prior to testing (pre-AAT) and 12 months following testing (post-AAT) were recorded for each patient. RESULTS: From the follow-up survey of 112 patients post-AAT, 95.2% (59/62) of patients with complete AAL removal expressed willingness to use 'de-labelled' antibiotics and 91.9% (57/62) were adherent to allergy label modification. Comparing antibiotic utilization 12 months pre-AAT versus 12 months post-AAT, AAT was associated with a significant increase in preferred antibiotic therapy [adjusted odds ratio (aOR) 3.29, 95% CI 1.56-6.92] and reduction in restricted antibiotic utilization (aOR 0.42, 95% CI 0.19-0.93). CONCLUSIONS: An antimicrobial stewardship (AMS)-led AAT programme was safe and effective in the long term in the promotion of preferred and narrow-spectrum antibiotic usage, and favourable patient perception towards the AAT testing results was identified. This study further supports the routine incorporation of AAT into AMS programmes, confirming safety and durability of testing impacts on patients as well as increasing preferred antibiotic utilization.

Baclofen acts in the central amygdala to reduce synaptic transmission and impair context fear conditioning.

The two main sub-divisions of the Central amygdala (CeA), the lateral-capsular (CeA-LC) and the medial (CeA-M), contain extensive networks of inhibitory interneurons. We have previously shown that activation of GABAB-receptors reduces excitatory transmission between axons of the pontine parabrachial nucleus and neurons of the CeA-LC by inhibiting glutamate release from presynaptic terminals13. Here we have characterised GABAB-receptor activation on other excitatory and inhibitory projections within the CeA. Using whole-cell, patch-clamp recordings, we found that the GABAB-receptor agonist baclofen significantly reduced excitatory and inhibitory transmission from all tested inputs into the CeA-LC and CeA-M. In all but one of the inputs, reductions in transmission were accompanied by an increase in paired pulse ratio, indicating that presynaptic GABAB-receptors acted to reduce the release probability of synaptic vesicles. To examine the impact of GABAB-receptors in the CeA on contextual fear-conditioning, we infused baclofen into the CeA immediately prior to training. Compared to vehicle-infused rats, baclofen-infused rats displayed significantly less freezing both during the final stages of the training period and at test 24 hours later. The results of this study demonstrate that, by suppressing excitatory and inhibitory transmission, activation of presynaptic GABAB-receptors in the CeA inhibits the development of context conditioned fear.

α2-adrenoceptor-mediated inhibition in the central amygdala blocks fear-conditioning.

The central amygdala is critical for the acquisition and expression of fear memories. This region receives a dense innervation from brainstem noradrenergic cell groups and has a high level of α2-adrenoceptor expression. Using whole-cell electrophysiological recordings from rat brain slices, we characterise the role of pre-synaptic α2-adrenoceptor in modulating discrete inhibitory and excitatory connections within both the lateral and medial division of the central amygdala. The selective α2-adrenoceptor agonist clonidine blocked the excitatory input from the pontine parabrachial neurons onto neurons of the lateral central amygdala. In addition, clonidine blocked inhibitory connections from the medial paracapsular intercalated cell mass onto both lateral and medial central amygdala neurons. To examine the behavioural consequence of α2-adrenoceptor-mediated inhibition of these inputs, we infused clonidine into the central amygdala prior to contextual fear-conditioning. In contrast to vehicle-infused rats, clonidine-infused animals displayed reduced levels of freezing 24 hours after training, despite showing no difference in freezing during the training session. These results reveal a role for α2-adrenoceptors within the central amygdala in the modulation of synaptic transmission and the formation of fear-memories. In addition, they provide further evidence for a role of the central amygdala in fear-memory formation.

Teaching critical thinking.

The ability to make decisions based on data, with its inherent uncertainties and variability, is a complex and vital skill in the modern world. The need for such quantitative critical thinking occurs in many different contexts, and although it is an important goal of education, that goal is seldom being achieved. We argue that the key element for developing this ability is repeated practice in making decisions based on data, with feedback on those decisions. We demonstrate a structure for providing suitable practice that can be applied in any instructional setting that involves the acquisition of data and relating that data to scientific models. This study reports the results of applying that structure in an introductory physics laboratory course. Students in an experimental condition were repeatedly instructed to make and act on quantitative comparisons between datasets, and between data and models, an approach that is common to all science disciplines. These instructions were slowly faded across the course. After the instructions had been removed, students in the experimental condition were 12 times more likely to spontaneously propose or make changes to improve their experimental methods than a control group, who performed traditional experimental activities. The students in the experimental condition were also four times more likely to identify and explain a limitation of a physical model using their data. Students in the experimental condition also showed much more sophisticated reasoning about their data. These differences between the groups were seen to persist into a subsequent course taken the following year.

Non-O1, non-O139 Vibrio cholerae bacteraemia in an Australian population.

This retrospective case series identifies the largest cohort of non-O1, non-O139 Vibrio cholerae bacteraemia in an Australian population from 2000 to 2013. We examine the risk factors, epidemiology, clinical presentations and mortality of non-O1, non-O139 V. cholerae bacteraemia in Victoria and compare them with published cases in the literature. This case series highlights the pathogenic potential of non-O1, non-O139 V. cholerae and identifies possible associations with host (underlying chronic liver disease and malignancy) and environmental factors (contaminated water supply and raw seafood). Clinicians should be aware of the morbidity and mortality associated with invasive non-O1, non-O139 V. cholerae infections, particularly in immunocompromised patients.

Eosinophilic cystitis in the pediatric population: a case series and review of the literature.

PURPOSE: Eosinophilic cystitis is a rarely seen condition in the pediatric population with indistinct symptomatology and non-standardized treatment protocols. We review our experience of treating patients with this condition. MATERIALS AND METHODS: We retrospectively reviewed the records of four patients from a single institution who have been diagnosed and treated for eosinophilic cystitis. In addition, the literature was reviewed for cases of pediatric eosinophilic cystitis. Our patients were added and compared to this cohort. RESULTS: Our patients included 3 females and 1 male who range in age from 5 days to 18 years (5 days, 1 month, 7 years, 18 years). Both of the infants presented with a suprapubic mass and bilateral hydroureteronephrosis. The two older patients both had dysuria while the 18 yo also complained of fatigue, flank pain, and hematuria. Only 2 of the 4 patients were found to have significant peripheral eosinophilia and only one patient had eosinophiluria. All of the patients were diagnosed via cystourethroscopy with biopsy. Treatment in each case consisted of a combination of steroids, antihistamines, and antibiotics. CONCLUSIONS: The presentation of eosinophilic cystitis is varied and diagnosis requires a high index of suspicion. Cystourethroscopy with biopsy is essential to establish the diagnosis as there is no typical appearance of the lesions or presenting signs/symptoms. Most cases of eosinophilic cystitis are responsive to medical therapy although in some cases recurrence may be noted.